1. Field of the Invention (Technical Field):
The present invention relates to nitration of fullerenes.
2. Description of Related Art
Fullerenes include C60, also known as hentriacontacyclo[29.29.0.0.2,14.03,12.04.59.05,10.06,58. 07,5508,53.09,21.011,20.013,18.015,30.016,28.017,25.019,24.022,52.023.50.026.49.027,47.029,45.032,44.033,60.034,57.035,43.036,56.037,41.038,54.039,51.040,48.042,46]hexaconta-1,3,5(10),6,8,11,13(18), 14,16,19,21,23,25,27,29(45),30,32(44),33,35(43), 36,38(54),39(51),40(48),41,46,49,52,55,57,59-triacontaene, the original “buckyball”—the perfectly spherical molecule consisting of 60 carbon atoms joined by alternating single and double bonds. Certain arrangements of alternating single and double bonds are known as aromatic systems in the field of chemistry, and indeed many of C60's interesting properties are due to this particular bonding arrangement between the atoms. Other buckyballs include C70, C76, C84, and C86.
In addition to buckyballs, fullerenes can be made to form long tubes in which the aforementioned spheres form the caps of the tubes, and at present the length of these carbon atom tubes can range up to many tens of microns in length. Indeed these “nanotubes” enjoy the same kind of “aromatic” carbon—carbon bonds as buckyballs, and similarly exhibit many unusual properties including electrical and thermal conductivity, strength, and additional properties. The most recent addition to the family of fullerenes is “buckypaper,” which is an agglomeration of nanotubes to form a thin sheet with exceedingly high strength. When properly formulated, such a nanotube matrix exhibits all the thermal conductivity, strength, and other properties of nanotubes, but is also stronger than steel.
Other species of fullerenes are fullerites (systems of doped solid state fullerenes) and fullerides (substitution of metal atoms for one or more carbon atoms) (see W. Kräjtschmer, et al., Physik in unserer Zeit 23 (1992) 105), endohedral fullerenes (atoms encaged in fullerene), exohedral fullerenes (atoms on exterior of fullerene), heterofullerenes (fullerenes in which carbon atoms have been replaced by heteroatoms) (see K. Esfarjani, et al., Phys. Rev. B 50 (1994) 17830; and G.-H. Chen, et al., Acta Physica Sinica (Overseas Edition) 6 (1997) 57), and metcars (metallocarbohedrenes, cage-like clusters of transition metal and carbon atoms) (see Jan-Ole Joswig, et al., Phys. Chem. Chem. Phys. 3 (2001) 5130).
For purposes of the specification and claims, “fullerene” is defined to include buckyballs, fullerites, fullerides, endohedral fullerenes, exohedral fullerenes, heterofullerenes, metcars, nanotubes, and buckypaper, and functionalized derivatives thereof.
It has not heretofore been appreciated that fullerenes could usefully be made explosive. U.S. Pat. No. 5,648,523, entitled “Fullerene Derivatives as Free-Radical Scavengers”, discloses in Example 6 the nitration of C60, but with the nitration step being part of an overall greater reaction with fullerene amino complexes as the product. The referenced nitrated reaction intermediate was C60 dodecanitrate, or C60(NO2)12 on average. Other patents mentioning nitration of C60 are U.S. Pat. No. 5,922,635, entitled “Nanoscale Solid Superacid Catalysts with Pendant Fluoroalkylsulfonic Acid or Fluoro, Perfluoroalkylsulfonic Acid Groups”; U.S. Pat. No. 5,756,726, entitled “Methods of Producing Singlet Oxygen Using Compounds Having Improved Functionalization”; U.S. Pat. No. 5,601,802, entitled “Methods of MRI Enhancement Using Compounds Having Improved Functionalization”; U.S. Pat. No. 5,599,928, entitled “Texaphyrin Compounds Having Improved Functionalization”; and U.S. Pat. No. 5,591,422, entitled “Texaphyrin Compounds Having Improved Functionalization”.
The present invention shows that the electrophillic substitution reaction known as nitration can not only be applied to C60 fullerenes but also related materials such as nanotubes and nanotube matrices. Furthermore any type of “ordnance” chemical functionality can be added to fullerenes or nanotubes to render an explosive and/or energetic material. Such high strength materials can be layered/formed into the structure or packaging of metals, ceramics, composites, electrical and/or mechanical discrete components. Such components can include active or passive sensors, circuit assemblies, packaging materials, fuselage materials, entire fuselages, wing structures, or other structures to which one wishes to impart explosive or ordnance characteristics.